posted at 2:12 pm on April 22, 2013 by Ed Morrissey

Canadian police and intelligence agencies will announce later today they have thwarted a plot to carry out a major terrorist attack, arresting suspects in Ontario and Quebec, CBC News has learned.

Highly placed sources tell CBC News the alleged plotters have been under surveillance for more than a year in Quebec and southern Ontario.

The investigation was part of a cross-border operation involving Canadian law enforcement agencies, the FBI and the U.S. Department of Homeland Security.

The arrests Monday morning were co-ordinated and executed by a special joint task force of RCMP and CSIS anti-terrorism units, combined with provincial and municipal police forces in Ontario and Quebec.

Authorities tell CBC News that this has no connection to the Boston attack. No motive or target(s) have yet been released, but the CBC is already referring to the Toronto 18 case from 2006, an Islamist plot to conduct a major terrorist attack in Canada.

Stand by for more details as they emerge.

Update: The RCMP has two people under arrest in a “bomb plot,” according to the Globe and Mail, but the report also notes this toward the end:

Several Muslim community leaders were called by Mounties early Monday to drop what they were doing and come at 2:30 p.m. to the RCMP police station near Toronto’s Pearson International Airport.

The G&M also reports that their sources indicate a smaller conspiracy than the Toronto 18.

Canadian police and intelligence agencies have made two arrests in connection with a planned major terrorist attack to derail a Via Rail passenger train in the Greater Toronto Area. Two suspects are in custody, one arrested in Toronto and one in Montreal, following an RCMP counter-terrorism investigation.

At an afternoon news conference, the RCMP named the suspects as Chiheb Esseghaier, 30, and Raed Jaser, 35, neither of whom are Canadian citizens, and said they were linked to al-Qaeda.

RCMP Assistant Commissioner James Malizia said that while the suspects had the capacity and intent to carry out an attack, there was no imminent threat to the general public, rail employees, train passengers or infrastructure.